Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
  1. Home
  2. /
  3. Compare
  4. /
  5. Claude Opus 5.5vsLaguna XS 2.1 (free)
Updated Sep 2026

Claude Opus 5.5vsLaguna XS 2.1 (free)

Laguna XS 2.1 (free) is cheaper than Claude Opus 5.5 at $0/M vs $4/M input tokens.

Claude Opus 5.5 and Laguna XS 2.1 (free) compared across 11 shared prompts
SpecClaude Opus 5.5Laguna XS 2.1 (free)
Input price$4/M tokensFree
Output price$20/M tokensFree
Context window1.0M tokens262K tokens
WeightsClosed—
Free API (OpenRouter)NoYes (1 provider)
ReleasedSep 2026Jul 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 11 prompts both answered. Formatting stripped, words untouched.

Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

Claude Opus 5.52,253 words
"Hive & Tide" Langoustine, Beeswax, White Chocolate & Oscietra Caviar, Hay-Baked Celeriac, Fermented Green Strawberry, Sea Buckthorn I. The Concept Most coastal menus celebrate the meeting of sea and land. This dish is about a stranger, quieter meeting: the meadow and the seabed, the bee and the langoustine.
Read the full answer
Laguna XS 2.1 (free)602 words
Recipe: "Nocturne of Shadows and Light" Concept: A poetic exploration of ancient flavors (pomegranate, quince) intertwined with modernist techniques (spherification, sous vide) and an unexpected coffee-cocoa depth, harmonizing the boldness of game with the elegance of fruit.
Read the full answer

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

Claude Opus 5.53,435 words
The Transistor in 1920: A Counterfactual Through 1980 First, a Reality Check on the Premise A transistor "invented" in 1920 would not have changed the world in 1920. The actual 1947 transistor rested on three foundations that did not exist yet: Quantum theory of solids.
Read the full answer
Laguna XS 2.1 (free)870 words
The Transistor Revolution: A 1920 Timeline Analysis Immediate Impact (1920-1940) Early Military Applications With transistors available 27 years before radar, telecommunications would see revolutionary improvements: Radio warfare: Nations could develop sophisticated radio direction-finding and jamming capabilities by…
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

Claude Opus 5.51,442 words
How Large Language Models Work: Three Explanations For the Experienced Software Engineer Think of an LLM as a single, very large pure function: f(tokens[0..n]) → probability distribution over tokens[n+1]. Text is chunked into tokens (roughly word fragments, from a vocabulary of about 100k).
Read the full answer
Laguna XS 2.1 (free)610 words
For the Software Engineer Think of training a language model like building a distributed prediction system with an incredibly complex API contract. Instead of training on labeled datasets where you explicitly tell it "this text is sentiment-positive," you're feeding it massive amounts of text and asking it to predict…
Read the full answer

Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Claude Opus 5.5653 words
Your 1-Month Starter Plan for Better Health & Longevity The philosophy: Small, consistent changes beat dramatic overhauls. Each week builds on the last, so by Day 30 you'll have a foundation of habits instead of a burned-out resolution.
Read the full answer
Laguna XS 2.1 (free)409 words
1-Month Health & Longevity Plan Focus Areas: Diet, Exercise, Sleep Week 1: Start with Foundational Habits Diet: Action: Add 1 serving of fruit or vegetables daily (e.g., a banana with breakfast, a side salad with lunch). Why: Boosts nutrient intake and fiber.
Read the full answer

Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

Claude Opus 5.53,099 words
The 90-Day Longevity & Performance Protocol A structured, measurable plan for the experienced biohacker How to Use This Plan Philosophy: Measure → Intervene → Re-measure. Every intervention has a hypothesis, a metric, and a decision rule.
Read the full answer
Laguna XS 2.1 (free)828 words
3-Month Longevity & Performance Optimization Plan for a Biohacker Designed for advanced biohackers with a focus on longevity, cognitive sharpness, and peak physical performance. Assumes access to basic medical testing, wearables, and some advanced tools (e.g., neurofeedback apps).
Read the full answer

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

Claude Opus 5.54,420 words
Contractor-Side Review of the Software Consulting Agreement Overall assessment: This agreement is heavily one-sided. Nearly every clause shifts risk, cost, or control to the Contractor, and several provisions interact to create compounding exposure.
Read the full answer
Laguna XS 2.1 (free)635 words
I'll analyze each clause in this software consulting agreement to identify potential risks to the contractor and suggest modifications with legal reasoning. Clause-by-Clause Analysis Clause 1: SCOPE Risk: Unlimited scope creep without additional compensation Modification: Add: "Any modification to the scope requiring…
Read the full answer
Our Verdict
Claude Opus 5.5
Claude Opus 5.5
Laguna XS 2.1 (free)
Laguna XS 2.1 (free)Runner-up

Not enough votes to call it. On the specs, Claude Opus 5.5 has the edge: newer, bigger context window, major provider backing.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 5.5
Input
$4.00
Output
$20.00
Laguna XS 2.1 (free)
Input
$0.000
Output
$0.000
Where to run it

5 hosts

Claude Opus 5.54 hosts
HostInOutContextUptime
Amazon Bedrock$4.00 in·$20.00 out·1M·99.8% upAzure AI Foundry$4.00 in·$20.00 out·1M·100% upAnthropic$4.00 in·$20.00 out·1M·100% upGoogle Vertex AI$4.00 in·$20.00 out·1M·100% up
Laguna XS 2.1 (free)1 host
HostInOutContextUptime
PPoolsidefp8$0 in·$0 out·262k·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Claude Opus 5.5 is developed by Anthropic while Laguna XS 2.1 (free) is developed by Poolside. Claude Opus 5.5 has a 1.0M token context window vs Laguna XS 2.1 (free)'s 262K. You can compare their actual outputs across 11 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 5.5 and Laguna XS 2.1 (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 11 challenges so you can judge which fits your needs best.

Claude Opus 5.5 costs $4/M input tokens and Laguna XS 2.1 (free) costs $0/M input tokens. Laguna XS 2.1 (free) is $4.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Claude Opus 5.5 and Laguna XS 2.1 (free) across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Keep exploring

More comparisons

Against the newest arrivals

Claude Opus 5.5 logoSolar Mini 4 logo
Claude Opus 5.5 vs Solar Mini 4Landed Sep 2026
Laguna XS 2.1 (free) logoQwen3.8 Max Prime logo
Laguna XS 2.1 (free) vs Qwen3.8 Max PrimeLanded Sep 2026
Claude Opus 5.5 logoGLM 5.3 Prime logo
Claude Opus 5.5 vs GLM 5.3 PrimeLanded Sep 2026
Laguna XS 2.1 (free) logoQwen3.8 Omni Flash logo
Laguna XS 2.1 (free) vs Qwen3.8 Omni FlashLanded Sep 2026
Claude Opus 5.5 logoCommand A+ logo
Claude Opus 5.5 vs Command A+Landed Sep 2026
Laguna XS 2.1 (free) logoGPT-6 Luna Pro logo
Laguna XS 2.1 (free) vs GPT-6 Luna ProLanded Sep 2026
Claude Opus 5.5 logoGPT-6 Sol Pro logo
Claude Opus 5.5 vs GPT-6 Sol ProLanded Sep 2026
Laguna XS 2.1 (free) logoGPT-6 Luna logo
Laguna XS 2.1 (free) vs GPT-6 LunaLanded Sep 2026

Same lab, same size, long tail

Claude Opus 5.5 logoClaude Opus 4.6 logo
Claude Opus 5.5 vs Claude Opus 4.6Same lab
Claude Opus 5.5 logoClaude Fable 5.1 logo
Claude Opus 5.5 vs Claude Fable 5.1Same lab
Laguna XS 2.1 (free) logoLaguna S 2.1 (free) logo
Laguna XS 2.1 (free) vs Laguna S 2.1 (free)Same lab
Laguna XS 2.1 (free) logoOx Alpha logo
Laguna XS 2.1 (free) vs Ox AlphaSame size
Laguna XS 2.1 (free) logoMercury logo
Laguna XS 2.1 (free) vs MercuryNew provider
Laguna XS 2.1 (free) logoMercury 2 logo
Laguna XS 2.1 (free) vs Mercury 2New provider
Claude Opus 5.5 logoMercury 2.5 logo
Claude Opus 5.5 vs Mercury 2.5Same size
Laguna XS 2.1 (free) logoMercury 2.5 Preview logo
Laguna XS 2.1 (free) vs Mercury 2.5 PreviewNew provider

Model pages

Claude Opus 5.5 logo
Claude Opus 5.519 outputs, specs and price
Laguna XS 2.1 (free) logo
Laguna XS 2.1 (free)11 outputs, specs and price
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed